SECTION 17.2 Summary

• Software fits the data to the model, producing estimates and of the parameters and . Software also produces standard errors for these estimates.

• A level confidence interval for the slope is

  A level confidence interval for the odds ratio is obtained by transforming the confidence interval for the slope,

  In these expressions, is the standard Normal critical value with area between and .

• The null hypothesis that does not help predict in the logistic regression model is or in terms of the odds ratio. To test this hypothesis, compute the test statistic

  17-16

  In terms of a random variable having a distribution with 1 degree of freedom, the -value for a test of against is approximately .